Recent developments in home and office automation systems provide both automatic and supervisory control of switched loads. In a home the loads typically consist of lights or outlet receptacles. In commercial applications motors and other type load devices might also be used. Existing automation systems include plural modules, typically one for each load, connected by custom wiring to permit automatic and supervisory control. Further improvements in automation systems contemplate eliminating the custom wiring. Instead, control signals are transmitted over the power wires using power line carrier technology. This allows automation to be used in both new construction and retrofit applications without additional wiring.
With the automation systems each module, such as for an outlet receptacle or wall switch, includes an electronic circuit for receiving and responding to commands, or initiating commands, from or to other modules. The electronic circuit requires power. Typically, power is provided by connecting to the hot and neutral power lines. However, a typical light circuit, such as for a ceiling light, often does not have the neutral wire at the switch. Instead, the neutral connection is made directly to the light fixture and only the hot wire is sent to the wall switch. Thus, there is a problem in powering a wall switch module without the presence of a neutral conductor. This can be resolved by stringing a neutral conductor through an existing conduit, if available. However, doing so requires additional wiring, eliminating one of the above-mentioned advantages of the further improved systems.
The present invention is directed to solving one or more problems discussed above, in a novel and simple manner.